Ground-based IR observation of oxygen isotope ratios in Venus׳s atmosphere

Iwagami, N.; Hashimoto, George L.; Ohtsuki, Shoko; Takagi, Seiko; Robert, Séverine

doi:10.1016/j.pss.2014.10.004

Cited by 7 publications

(3 citation statements)

References 15 publications

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“…Recent ground-based IR observations of the Venusian atmosphere yield deviations in the three-oxygen isotope system that overlap with the Earth-Moon fractionation line within errors. This is the expected result if the material that gave rise to Venus was mixed with that which built the Earth (Iwagami et al, 2015).…”

Section: Discussionmentioning

confidence: 63%

The cool and distant formation of Mars

Brasser

Mojzsis

Matsumura

et al. 2017

Earth and Planetary Science Letters

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The cool and distant formation of MarsBrasser, R.; Mojzsis, S. J. ; Matsumura, S.; Ida, S. General rightsCopyright and moral rights for the publications made accessible in Discovery Research Portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights.• Users may download and print one copy of any publication from Discovery Research Portal for the purpose of private study or research.• You may not further distribute the material or use it for any profit-making activity or commercial gain.• You may freely distribute the URL identifying the publication in the public portal. Take down policyIf you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim. AbstractWith approximately one ninth of Earth's mass, Mars is widely considered to be a stranded planetary embryo that never became a fully-grown planet. A currently popular planet formation theory predicts that Mars formed near Earth and Venus and was subsequently scattered outwards to its present location. In such a scenario, the compositions of the three planets are expected to be similar to each other. However, bulk elemental and isotopic data for martian meteorites demonstrate that key aspects of Mars' composition are markedly different from that of Earth. This suggests that Mars formed outside of the terrestrial feeding zone during primary accretion. It is therefore probable that Mars always remained significantly farther from the Sun than Earth; its growth was stunted early and its mass remained relatively low. Here we identify a potential dynamical pathway that forms Mars in the asteroid belt and keeps it outside of Earth's accretion zone while at the same time accounting for strict age and compositional constraints, as well as mass differences. Our uncommon pathway (approximately 2% probability) is based on the Grand Tack scenario of terrestrial planet formation, in which the radial migration by Jupiter gravitationally sculpts the planetesimal disc at Mars' current location. We conclude that Mars' formation requires a specific dynamical pathway, while this is less valid for Earth and Venus. We further predict that Mars' volatile budget is most likely different from Earth's and that Venus formed close enough to our planet that it is expected to have a nearly identical composition from common building blocks.

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Section: Discussionmentioning

confidence: 63%

The cool and distant formation of Mars

Brasser

Mojzsis

Matsumura

et al. 2017

Earth and Planetary Science Letters

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“…An observation of oxygen fractionation in CO 2 could indicate extreme atmospheric loss but may be difficult to achieve. The fractional mass difference between 18 O and 16 O is small, and Venus does not exhibit fractionation in oxygen (Hoffman et al 1980;Bezard et al 1987;Iwagami et al 2015). So significant fractionation in oxygen may require atmospheric escape mechanisms unknown in our solar system, or operating over longer time periods or at higher fluxes than for the solar system planets.…”

Section: Discussionmentioning

confidence: 97%

Observing Isotopologue Bands in Terrestrial Exoplanet Atmospheres with the James Webb Space Telescope: Implications for Identifying Past Atmospheric and Ocean Loss

Lincowski

Lustig‐Yaeger

Meadows

2019

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Terrestrial planets orbiting M dwarfs may soon be observed with the James Webb Space Telescope (JWST) to characterize their atmospheric composition and search for signs of habitability or life. These planets may undergo significant atmospheric and ocean loss due to the superluminous pre-main-sequence phase of their host stars, which may leave behind abiotically-generated oxygen, a false positive for the detection of life. Determining if ocean loss has occurred will help assess potential habitability and whether or not any O 2 detected is biogenic. In the solar system, differences in isotopic abundances have been used to infer the history of ocean loss and atmospheric escape (e.g. Venus, Mars). We find that isotopologue measurements using transit transmission spectra of terrestrial planets around late-type M dwarfs like TRAPPIST-1 may be possible with JWST, if the escape mechanisms and resulting isotopic fractionation were similar to Venus. We present analyses of post-ocean-loss O 2 -and CO 2 -dominated atmospheres, containing a range of trace gas abundances. Isotopologue bands are likely detectable throughout the near-infrared (1-8 µm), especially 3-4 µm, although not in CO 2 -dominated atmospheres. For Venus-like D/H ratios 100 times that of Earth, TRAPPIST-1 b transit signals of up to 79 ppm are possible by observing HDO. Similarly, 18 O/ 16 O ratios 100 times that of Earth produce signals at up to 94 ppm. Detection at S/N=5 may be attained on these bands with as few as four to eleven transits, with optimal use of JWST NIRSpec Prism. Consequently, H 2 O and CO 2 isotopologues could be considered as indicators of past ocean loss and atmospheric escape for JWST observations of terrestrial planets around M dwarfs.

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“…Furthermore, because of its large dissociation energy and the relatively high abundance of its constituent atoms, carbon monoxide in its several isotopic forms is observed in a variety of astrophysical sources, including erupting supernovae, stellar photospheres, comets, and the interstellar medium, see e.g., Romano et al (2017), Iwagami et al (2015), Banerjee et al (2018), and references therein.…”

Section: Introductionmentioning

confidence: 99%

Analysis of the first overtone bands of isotopologues of CO and SiO in stellar spectra

Pavlenko

Yurchenko

Tennyson

2020

A&A

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Context. The first overtone (∆v = 2) bands of the monosubstituted isotopologues of CO at 2.3 µm in the spectrum of Arcturus (K2 III), and of the monosubstituted isotopologues of SiO at 4 µm in the spectrum of the red giant HD196610 (M6 III) are modelled. Aims. To investigate problems involving the computation of the first overtone bands of isotopologues of CO and SiO in spectra of late-type stars and to determine isotopic abundances. Methods. We use fits of theoretical synthetic spectra to the observed stellar molecular bands of CO and SiO to determine abundances of isotopes of C, O and Si. Results. Fits of synthetic spectra of the 12 C 16 O first overtone bands at 2.3 µm computed with three available line lists (Goorvitch, HITEMP2010 and Li et al.) to the observed spectrum of Arcturus provide the same carbon abundance [C]=−0.6 and isotopic ratio of carbon 12 C/ 13 C =10 ± 2. However, the quality of fits to the observed spectrum differ for three line lists used. Furthermore, the derived oxygen isotopic ratio 16 O/ 18 O = 2000 ± 500 is larger than that known in the solar system where 16 O/ 18 O = 500. The silicon isotopic ratio in the atmosphere of the red giant HD196610 is revised. Using the ExoMol SiO line list with appropriate statistical weights for the SiO isotopologues the 'non-solar' ratio 28 Si: 29 Si: 30 Si = 0.86±0.03:0.12±0.02:0.02±0.01 is obtained. Conclusions. We found that a) the computed isotopic carbon and silicon ratios determined by the fits to the observed spectrum depend on the adopted abundance of C and Si, respectively; b) Correct treatment of the nuclear spin degeneracies parameter is of crucial importance for the use of nowadays HITRAN/ExoMol line lists in the astrophysical computations.Article number, page 1 of 9

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Ground-based IR observation of oxygen isotope ratios in Venus׳s atmosphere

Cited by 7 publications

References 15 publications

The cool and distant formation of Mars

The cool and distant formation of Mars

Observing Isotopologue Bands in Terrestrial Exoplanet Atmospheres with the James Webb Space Telescope: Implications for Identifying Past Atmospheric and Ocean Loss

Analysis of the first overtone bands of isotopologues of CO and SiO in stellar spectra

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